How to detect an error in item creation on the client side (App Maker)

Question

I am creating an app to store schedules and I do not want two schedules with the same date. To combat this I added this code (javascript) to the onBeforeCreate() and onBeforeSave() events.

var query = app.models.DataSource.newQuery(); // New query

query.filters.date._equals = record.date; //Search for a record that has the same 

if (query.run().length) {
  throw new Error("There is already a schedule on that date"); // Throw an error
}

This works great to prevent the duplicate entries, but how would I go about detecting this on the client side and reporting it to the user?

Its probably a quick fix but any input would be greatly appreciated :)

Thanks!!

Answer 1

First, you need to modify the datasource field to be unique.
You'll need to go to ModelName > FieldName > Advanced:

Then, when creating the item on the client side, let's say, for example, using a button widget which its datasource is set in create mode, then on the onClick event handler, use the following:

widget.datasource.createItem({
  success: function(record){
    console.log(record._key);
  },
  failure: function(error){
    var err = error.toString();
    if(err.indexOf("Duplicate entry") > -1){
      alert("There is already a schedule on that date");
    } else {
      alert(error.toString());
    }
  }    
});

For more information, I recommend you to consult the official documentation.